package org.nobject.common.js;

/**
 * 转义字符工具类
 *
 * @author bianrongjun
 * @version 1.0
 */
public class EscapeUtils {
	
	/**
	 * 将字符串转成转义字符串
	 * @param str 字符串
	 */
	public static String escape(String str) {
		int i;
		char j;
		StringBuffer tmp = new StringBuffer();
		tmp.ensureCapacity(str.length() * 6);
		for (i = 0; i < str.length(); i++) {
			j = str.charAt(i);
			if (Character.isDigit(j) || Character.isLowerCase(j) || Character.isUpperCase(j))
				tmp.append(j);
			else if (j < 256) {
				tmp.append("%");
				if (j < 16)
					tmp.append("0");
				tmp.append(Integer.toString(j, 16));
			} else {
				tmp.append("%u");
				tmp.append(Integer.toString(j, 16));
			}
		}
		return tmp.toString();
	}

	/**
	 * 将转义字符转换成字符串
	 * @param str 字符串
	 */
	public static String unescape(String str) {
		StringBuffer tmp = new StringBuffer();
		tmp.ensureCapacity(str.length());
		int lastPos = 0, pos = 0;
		char ch;
		while (lastPos < str.length()) {
			pos = str.indexOf("%", lastPos);
			if (pos == lastPos) {
				if (str.charAt(pos + 1) == 'u') {
					ch = (char) Integer.parseInt(str.substring(pos + 2, pos + 6), 16);
					tmp.append(ch);
					lastPos = pos + 6;
				} else {
					ch = (char) Integer.parseInt(str.substring(pos + 1, pos + 3), 16);
					tmp.append(ch);
					lastPos = pos + 3;
				}
			} else {
				if (pos == -1) {
					tmp.append(str.substring(lastPos));
					lastPos = str.length();
				} else {
					tmp.append(str.substring(lastPos, pos));
					lastPos = pos;
				}
			}
		}
		return tmp.toString();
	}
	
    public static void main(String[] args) {    
        String tmp = "中文";    
        System.out.println("testing escape : " + tmp);    
        tmp = escape(tmp);    
        System.out.println(tmp);    
        System.out.println("testing unescape :" + tmp);    
        System.out.println(unescape("%u6211%u4eec"));    
    }    
}
